Automatic gain control is employed in a variety of applications, for example, to adjust gain as a function of an input signal or other parameters. A typical automatic gain control (AGC) circuit utilizes only analog techniques to control gain, such as for example by varying a bias current or a load resistance. Consequently, these types of AGC circuits are generally limited in their allowable linear dynamic range and/or speed of operation.
A conventional AGC circuit may also employ a peak amplitude detection circuit to sense an output signal amplitude level of the AGC circuit. A drawback of a typical peak amplitude detection circuit is its limited speed of operation, which generally limits the overall speed of operation for the AGC circuit. As a result, there is a need for improved techniques for automatic gain control.